[scooder]

Nothing wrong with using detergent oil in an engine that's only had non detergent oil before, I used to think that it would be bad. That the detergent oil would free up the sludge and whip it around the engine. But it don't do that, it ain't ment to and can't do that. It only keeps the bits in suspension that come loose, for want of a better description, while the detergent oil was/is in use. It won't clean old sludge and stuff out of the pan. I've seen pics of a valve chamber on s flathead that used non detergent for years, then a switch to detergent oil years later, still has all the old (pre detergent) sludge in there.
Use good detergent oil.
Martin.